Battery, manufacturing method thereof and electronic product

Abstract

The present disclosure provides a battery, a manufacturing method thereof and an electronic product. The battery cell includes electrodes and tabs, where each of the electrodes includes a current collector and an active material layer, and the current collector includes a coating zone coated with the active material layer and an empty foil zone, and an end of a tab overlaps the empty foil zone and the tab and the empty foil zone are connected by laser welding; the side of the empty foil zone facing away from the tab has a plurality of dot-shaped welding marks arranged at intervals, and the dot-shaped welding marks include a concave part and an annular convex part surrounding the concave part. The contact area between the annular convex part and the separator between the positive electrode and the negative electrode is large, and the separator is less likely to be pierced.

What is claimed is: 
     
       1. A battery, comprising a housing and a battery cell accommodated in the housing, wherein
 the battery cell comprises electrodes and tabs, wherein each of the electrodes comprises a current collector and an active material layer, the current collector comprises a coating zone coated with the active material layer and an empty foil zone not coated with the active material layer, an end of a tab overlaps the empty foil zone and the tab and the empty foil zone are fixedly connected by laser welding; 
 a surface of the empty foil zone facing away from the tab has a plurality of dot-shaped welding marks arranged at intervals, and each of the dot-shaped welding marks comprises a concave part and an annular convex part surrounding a periphery of the concave part; and 
 a surface of the tab facing away from the empty foil zone has no welding mark; 
 wherein the plurality of dot-shaped welding marks are arranged in an array; and 
 a number of the dot-shaped welding marks is between 150 and 800; 
 a minimum distance between a dot-shaped welding mark and the coating zone is larger than 1 mm; 
 a height of the annular convex part is within 30 μm; 
 a depth of the concave part is smaller than a sum of thicknesses of the empty foil zone and the tab; and 
 a bottom surface of the concave part has a central convex part, and a height of the central convex part is smaller than a depth of the concave part. 
 
     
     
       2. The battery according to  claim 1 , wherein the depth of the concave part is between 20 μm and 70 μm. 
     
     
       3. The battery according to  claim 1 , wherein a sidewall of the concave part at least has a partial cylindrical wall surface or a partial truncated cone-shaped wall surface. 
     
     
       4. The battery according to  claim 1 , wherein a diameter of a dot-shaped welding mark is between 50 μm and 300 μm; and,
 a distance between two adjacent dot-shaped welding marks is not less than 100 μm. 
 
     
     
       5. The battery according to  claim 1 , wherein the empty foil zone is located in a middle of the electrode. 
     
     
       6. An electronic product, comprising the battery according to  claim 1 . 
     
     
       7. The battery according to  claim 1 , wherein a diameter of a dot-shaped welding mark is between 50 μm and 300 μm. 
     
     
       8. The battery according to  claim 1 , wherein a distance between two adjacent dot-shaped welding marks is not less than 100 μm. 
     
     
       9. The battery according to  claim 1 , wherein the empty foil zone is located in a middle of the electrode. 
     
     
       10. A manufacturing method of a battery, comprising:
 providing electrodes, tabs and a separator, wherein each of the electrodes has a coating zone and an empty foil zone; 
 for each pair of an electrode and a tab, attaching the empty foil zone of the electrode to the tab; performing by using a laser welding device, pulse dot welding from a surface of the empty foil zone facing away from the tab to form a plurality of dot-shaped welding marks arranged at intervals; each of the dot-shaped welding marks comprising a concave part and an annular convex part surrounding a periphery of the concave part; a surface of the tab facing away from the empty foil zone has having no welding mark, wherein the plurality of dot-shaped welding marks are arranged in an array; and a number of the dot-shaped welding marks is between 150 and 800; and a minimum distance between a dot-shaped welding mark and the coating zone is larger than 1 mm; a height of the annular convex part is within 30 μm; a depth of the concave part is smaller than a sum of thicknesses of the empty foil zone and the tab; and a bottom surface of the concave part has a central convex part, and a height of the central convex part is smaller than a depth of the concave part; 
 processing the electrodes welded with the tabs and a separator together to form a battery cell; and 
 assembling the battery cell into a housing to form the battery.